Energy storage cell

Abstract

To provide a power storage cell that can reduce shortage of an electrolytic solution in a wound assembly.SOLUTION: A power storage cell 1 includes an electrode assembly 100, a cell case that houses the electrode assembly, and an electrolytic solution contained in the cell case. The electrode assembly 100 includes: a wound assembly 101 in which the positive electrode sheet and the negative electrode sheet are wound with the separator interposed therebetween; a first tape 141 attached to one end portion of the wound assembly 101 in an axial direction of the wound assembly 101; and a second tape 142 attached to the other end portion of the wound assembly 101 in the axial direction. Force of fixing the wound assembly 101 by the first tape 141 is smaller than force of fixing the wound assembly by the second tape 142.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a storage battery cell.

Background Art

[0002] International Publication No. 2018 / 168628 discloses a non-aqueous electrolyte secondary battery including a wound body in which a positive electrode plate and a negative electrode plate are wound with a separator interposed therebetween, and a battery case that houses the wound body and a non-aqueous electrolyte. The end of the wound body is fixed with a tape. Specifically, tapes are attached to one end and the other end in the axial direction of the wound body of the wound body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the non-aqueous electrolyte secondary battery described in International Publication No. 2018 / 168628, there is a concern that the electrolyte solution is insufficient in the wound body because the electrolyte solution flows out of the wound body particularly during high-rate charge and discharge.

[0005] An object of the present disclosure is to provide a storage battery cell capable of suppressing a shortage of the electrolyte solution in the wound body. [[ID=]]

Means for Solving the Problems

[0006] A storage cell according to one aspect of the present disclosure comprises an electrode body, a cell case housing the electrode body, and an electrolyte housed in the cell case, wherein the electrode body comprises a winding body formed by winding a positive electrode sheet and a negative electrode sheet with a separator in between, a first tape attached to one end of the winding body in the axial direction, and a second tape attached to the other end of the winding body in the axial direction, wherein the fixing force of the winding body by the first tape is less than the fixing force of the winding body by the second tape. [Effects of the Invention]

[0007] According to this disclosure, it is possible to provide an energy storage cell that can suppress electrolyte shortage in the wound body. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic cross-sectional view showing a storage cell in one embodiment of the present disclosure. [Figure 2] This is a schematic front view showing the electrode body. [Figure 3] This is a cross-section of the first tape. [Figure 4] This is a cross-section of the second tape. [Modes for carrying out the invention]

[0009] Embodiments of this disclosure will be described with reference to the drawings. In the drawings referred to below, the same or equivalent components are given the same number.

[0010] Figure 1 is a schematic partial cross-sectional view showing an energy storage cell in one embodiment of the present disclosure. Figure 2 is a schematic front view showing an electrode body. This energy storage cell 1 is preferably mounted in a vehicle.

[0011] As shown in Figures 1 and 2, the energy storage cell 1 comprises an electrode body 100, a cell case 200, an external terminal 300, a positive electrode current collector plate 410, a negative electrode current collector plate 420, an insulating member 500, and an electrolyte (not shown).

[0012] As shown in Figure 2, the electrode body 100 includes a wound body 101, a first tape 141, and a second tape 142.

[0013] The winding body 101 includes a positive electrode sheet 110, a negative electrode sheet 120, and a separator 130. The winding body 101 is formed by winding the positive electrode sheet 110 and the negative electrode sheet 120 around a winding core A (see Figure 1) via the separator 130.

[0014] The positive electrode sheet 110 includes a positive electrode current collector foil 112 and a positive electrode active material layer 114.

[0015] The positive electrode current collector foil 112 is made of a metal such as aluminum. The positive electrode current collector foil 112 has a main region 112a and an end region 112b.

[0016] The main region 112a is the region of the positive electrode current collector foil 112 in which the positive electrode active material layer 114 is provided. As shown in Figure 1, the main regions 112a are arranged to overlap each other in the radial direction (left-right direction in Figure 1) of the electrode body 100.

[0017] The end region 112b is the region of the positive electrode current collector foil 112 in which the positive electrode active material layer 114 is not provided. As shown in Figure 1, the end region 112b is formed on the outside (upper side in Figure 1) of the main region 112a in the axial direction (up and down direction in Figure 1) of the electrode body 100.

[0018] The end region 112b has a plurality of tabs that are separated from each other in the circumferential direction of the electrode body 100. Each tab 112b1 is bent inward in the radial direction. The upper surface of each tab forms a substantially flat surface. A positive electrode current collector plate 410 is connected to each tab by welding or the like.

[0019] The negative electrode sheet 120 includes a negative electrode current collector foil 122 made of a metal such as copper, and a negative electrode active material layer 124 provided on the surface of the negative electrode current collector foil 122.

[0020] The structure of the negative electrode current collector foil 122 is substantially the same as that of the positive electrode current collector foil 112. Therefore, the description of the negative electrode current collector foil 122 is simplified. That is, the negative electrode current collector foil 122 has a main region 122a provided with a negative electrode active material layer 124 and an end region 122b formed outside the main region 122a in the axial direction (the lower side in FIG. 1). The end region 122b has a plurality of tabs separated from each other in the circumferential direction, and each tab is inclined inward in the radial direction. A negative electrode current collector plate 420 is connected to each tab by welding or the like.

[0021] The separator 130 is disposed between the positive electrode sheet 110 and the negative electrode sheet 120. More specifically, the separator 130 is disposed only between the main region 112a of the positive electrode sheet 110 and the main region 122a of the negative electrode sheet 120 adjacent to each other in the radial direction. The separator 130 is made of an insulating material and allows the permeation of ions.

[0022] The first tape 141 is attached to one end of the wound body 101 in the axial direction (the vertical direction in FIG. 2) of the wound body 101. The second tape 142 is attached to the other end of the wound body 101 in the axial direction. In the present embodiment, the first tape 141 is provided below the second tape 142 in the vertical direction. That is, the first tape 141 is attached to the lower end of the wound body 101, and the second tape 142 is attached to the upper end of the wound body 101. As shown in FIG. 2, the first tape 141 and the second tape 142 are attached to the wound body 101 so as to straddle the end 139 of the wound body 101. Note that the first tape 141 and the second tape 142 may be annularly connected in the circumferential direction of the wound body 101. As shown in FIG. 2, the first tape 141 and the second tape 142 are attached to the wound body 101 so as to straddle the end 139 of the wound body 101. Note that the first tape 141 and the second tape 142 may be annularly connected in the circumferential direction of the wound body 101.

[0023] As shown in Figure 3, the first tape 141 has a first base layer 141a and a first adhesive layer 141b provided on the first base layer 141a. The first base layer 141a is made of, for example, polypropylene (PP), polyimide (PI), polyethylene (PE), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), etc. The first adhesive layer 141b is made of, for example, an acrylic or silicone adhesive.

[0024] As shown in Figure 4, the second tape 142 has a second base layer 142a and a second adhesive layer 142b provided on the second base layer 142a. The second base layer 142a is made of the same material as the first base layer 141a. The first adhesive layer 141b is made of the same material as the first adhesive layer 141b.

[0025] The fixing force of the winding body 101 by the first tape 141 is less than the fixing force of the winding body 101 by the second tape 142. In this embodiment, as shown in Figure 2, the bonding area of ​​the first adhesive layer 141b to the winding body 101 is set to be smaller than the bonding area of ​​the second adhesive layer 142b to the winding body 101.

[0026] However, the bonding area of ​​the first adhesive layer 141b to the wound body 101 and the bonding area of ​​the second adhesive layer 142b to the wound body 101 may be set to be equal to each other, and the adhesive force of the first adhesive layer 141b may be set to be less than the adhesive force of the second adhesive layer 142b. For example, if each adhesive layer 141b and 142b consists of a silicone-based adhesive, the mixing ratio of the silicone rubber that ensures adhesion and the silicone resin that ensures adhesion may be different in each adhesive layer 141b and 142b. In other words, the mixing ratio of the silicone resin in the first adhesive layer 141b may be set to be less than the mixing ratio of the silicone resin in the second adhesive layer 142b. Alternatively, the molecular weight of the polymer in the first adhesive layer 141b may be set to be less than the molecular weight of the polymer in the second adhesive layer 142b.

[0027] The cell case 200 houses the electrode body 100. An electrolyte solution (not shown) is contained inside the cell case 200. The cell case 200 is sealed. The cell case 200 is made of a metal such as aluminum. The cell case 200 has a cylindrical section 210, a top wall 220, and a bottom wall 230.

[0028] The cylindrical portion 210 surrounds the outer surface of the electrode body 100.

[0029] The top wall 220 is connected to the upper end of the cylindrical portion 210. A through hole for inserting the external terminal 300 is formed in the center of the top wall 220.

[0030] The bottom wall 230 is connected to the lower end of the cylindrical portion 210 by welding or the like. The bottom wall 230 is in contact with the negative electrode current collector plate 420.

[0031] The external terminal 300 is formed above the top wall 220. In this embodiment, the external terminal 300 constitutes the positive external terminal. The cell case 200 constitutes the negative external terminal.

[0032] The insulating member 500 insulates the cell case 200 and the external terminals 300. The insulating member 500 has an upper insulating portion 510 and a lower insulating portion 520.

[0033] The upper insulating portion 510 is provided on the upper surface of the top wall 220. The upper insulating portion 510 is interposed between the upper surface of the top wall 220 and the external terminal 300.

[0034] The lower insulating section 520 is provided on the lower surface of the top wall 220. The lower insulating section 520 is interposed between the positive electrode current collector plate 410 and the cell case 200.

[0035] As described above, in the energy storage cell 1 of this embodiment, the fixing force of the winding body 101 by the first tape 141 is smaller than the fixing force of the winding body 101 by the second tape 142. Therefore, the electrolyte retention space at one end of the winding body 101 is larger than the electrolyte retention space at the other end of the winding body 101. As a result, electrolyte that has leaked out of the winding body 101 during charging and discharging can easily return to the winding body 101. Thus, electrolyte shortage in the winding body 101 is suppressed.

[0036] Those skilled in the art will understand that the exemplary embodiments described above are specific examples of the following embodiments.

[0037] [Aspect 1] Electrode body and A cell case for housing the electrode body, The cell case contains an electrolyte solution, The electrode body is A winding body in which a positive electrode sheet and a negative electrode sheet are wound around each other with a separator in between, The first tape attached to one end of the aforementioned wound body in the axial direction, The winding body comprises a second tape attached to the other end in the axial direction, A storage cell in which the fixing force of the winding body by the first tape is less than the fixing force of the winding body by the second tape.

[0038] In this energy storage cell, the fixing force of the winding body by the first tape is less than the fixing force of the winding body by the second tape. As a result, the electrolyte retention space at one end of the winding body is larger than the electrolyte retention space at the other end. Therefore, electrolyte that has leaked out of the winding body during charging and discharging can easily return to the winding body. Thus, electrolyte shortage in the winding body is suppressed.

[0039] [Aspect 2] The energy storage cell according to embodiment 1, wherein the first tape is provided below the second tape in the vertical direction.

[0040] In this embodiment, the electrolyte retention space becomes relatively larger at the lower part of the winding body, making it easier for the electrolyte accumulated at the bottom of the cell case to flow into the winding body from the bottom.

[0041] [Aspect 3] The first tape has a first adhesive layer, The second tape has a second adhesive layer, The energy storage cell according to embodiment 1 or 2, wherein the bonding area of ​​the first adhesive layer to the winding body is smaller than the bonding area of ​​the second adhesive layer to the winding body.

[0042] In this embodiment, since the adhesive area of ​​each adhesive layer on the winding body is different, the fixing force of the first tape on the winding body becomes smaller than the fixing force of the second tape on the winding body.

[0043] [Aspect 4] The first tape has a first adhesive layer, The second tape has a second adhesive layer, The energy storage cell according to embodiment 1 or 2, wherein the adhesive force of the first adhesive layer to the winding body is less than the adhesive force of the second adhesive layer to the winding body.

[0044] In this embodiment, since the adhesive strength of each adhesive layer to the winding body is different, the fixing force of the first tape to the winding body becomes smaller than the fixing force of the second tape to the winding body.

[0045] It should be noted that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the description of the embodiments above, and further includes all modifications within the meaning and scope equivalent to the claims. [Explanation of Symbols]

[0046] 1 Energy storage cell, 100 Electrode body, 101 Winding body, 110 Positive electrode sheet, 112 Positive current collector foil, 112a Main region, 112b End region, 114 Positive active material layer, 120 Negative electrode sheet, 122 Negative current collector foil, 122a Main region, 122b End region, 124 130 Negative electrode active material layer, 141 separator, 141 first tape, 141a first base material layer, 141b first adhesive layer, 142 second tape, 142a second base material layer, 142b second adhesive layer, 200 cell case, 210 case body, 220 top wall, 230 bottom wall, 300 external terminal, 410 positive electrode current collector plate, 420 negative electrode current collector plate, 510 insulating material.

Claims

1. Electrode body and A cell case for housing the electrode body, The positive terminal external terminal, The cell case contains an electrolyte solution, The electrode body is A winding body in which a positive electrode sheet and a negative electrode sheet are wound around each other with a separator in between, The first tape attached to one end of the aforementioned winding body in the axial direction, The winding body comprises a second tape attached to the other end in the axial direction, The aforementioned cell case is A cylindrical portion surrounding the electrode body, The top wall is connected to the upper end of the cylindrical portion, It has a bottom wall connected to the lower end of the cylindrical portion, The external terminal of the positive electrode is formed above the top wall, The second tape is provided closer to the top wall than the first tape. A storage cell in which the fixing force of the winding body by the first tape is less than the fixing force of the winding body by the second tape.

2. The energy storage cell according to claim 1, wherein the second tape is connected in an annular manner in the circumferential direction to the electrode body.

3. The first tape has a first adhesive layer, The second tape has a second adhesive layer, The energy storage cell according to claim 1 or 2, wherein the bonding area of ​​the first adhesive layer to the winding body is smaller than the bonding area of ​​the second adhesive layer to the winding body.

4. The first tape has a first adhesive layer, The second tape has a second adhesive layer, The energy storage cell according to claim 1 or 2, wherein the adhesive force of the first adhesive layer to the winding body is less than the adhesive force of the second adhesive layer to the winding body.

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